Various membrane proteins are disposed on the surface of cells constituting an organism. Channels, which are openings of membrane proteins, are opened or closed by binding of chemicals (signaling substances such as ligands) to specific sites on the cell surface or electrical or photic stimulation (gate trigger), resulting in regulation of the transport of ions or chemicals between the outside and inside of cell membrane. This regulation is performed by ion channels, which are important membrane proteins involved in signal transduction in biological systems. In measurement of their function or development of drugs related to the function, measurement of electrical changes in channel proteins, i.e., ion channel current, is required.
To meet this demand, technologies such as pipette patch clamp and planar patch clamp have been developed. Pipette patch clamp has a drawback that it cannot be applied to high-throughput screening by multipoint measurement. On the other hand, planar patch clamp constitutes a plurality of patch clamp devices on a solid substrate such as silicon tip, thereby enabling multipoint measurement. Each patch clamp device includes fine through holes to measure an ion channel current at each cell placement site.
For example, the following Patent Literature 1 mentions a planar patch clamp electrode array including a plurality of electrodes in order to perform patch clamp recording with a plurality of patch clamp cells. The following Patent Literature 2 discloses a planar patch clamp device which is disposed with electrodes disposed on the upper and lower surfaces of a silicon substrate, and a through hole that conductively communicate between the two electrodes, thus measuring electrical changes in a cell disposed on the through hole.